With an increasingly vocal demand for reduction in operating costs of corporate IT systems, use of a data center that accommodates the corporate IT systems is increasing. A system of the data center is formed of a plurality of servers and network devices, and is therefore large in power consumption. In the data center, there occurs addition or deletion of a server due to the start or termination of use of a service by a customer as well as an expansion of a scale of the data center and a change in network configuration due to an increase in the number of users. It is demanded that the data center handle the above-mentioned change in configuration and suppress the power consumption.
With regard to servers among the components of a data center system, there is a method involving consolidating task execution processes onto a small number of servers in agreement with the lowering of task load and shutting down power to a server on which no process is running (see, for example, JP 2007-310791 A). JP 2007-310791 A discloses a method for satisfying the demanded performance and reducing power consumption of a server system by migrating a task process on the server onto a plurality of servers or consolidating task processes onto a single server in agreement with an increase/decrease of the task load and by shutting down power supply to the server on which no task process is running.
Further, with regard to a network among the components of the data center system, there is a conventional technology for lowering an operating frequency of a forwarder of a switch when a volume of traffic decreases (see, for example, JP 07-336381 A). JP 07-336381 A discloses a switch configuring method for lowering power consumption by suppressing the operation of the forwarder that relays frames between ports when there is no frame reaching the port of the switch. Further, there is a network system configuring method involving shifting to a power-saving operation mode in agreement with the volume of traffic while decreasing a shutdown time period of a frame transfer (see, for example, JP 2005-123715 A).